The present invention relates to surgical clips of the type referred to as parallel jaw clips, and improved methods for assembling such clips.
In many surgical procedures, a considerable number of surgical clips are used to occlude severed blood vessels and other body conduits. A common type of clip is the parallel jaw clip which includes a pair of jaws at least one of which is moveable to open and close the jaws of the clip. Parallel jaw clips have a number of advantages over other types of surgical clips. Some of the advantages include easy and dependable placement on a blood vessel, reliable occlusion when so placed, and simple removal as the surgery is completed. Parallel jaw clips must be economical to manufacture so they can be discarded after use. This is because of the difficulty involved in sterilizing and reusing the clips.
Clips of the past have frequently failed to meet all of these design, cost, and performance criteria. Many clips have been designed and produced with component parts which must be adhesively bonded together. Use of adhesives having the necessary bonding strength and long-term durability usually requires a set time which adds to the production cost. Also, adhesive overflow or flow outside the joint to be bonded can require a clean-up step or the discarding of defective clips. It would be advantageous to have a surgical clip of the parallel jaw design which is economical to produce, dependable to use, and designed for easy application and removal from a blood vessel.
The prior art relating to parallel jaw surgical clips is represented by U.S. Pat. No. 4,931,058 issued to Cooper and entitled PARALLEL JAW SPRING CLIP AND METHOD OF MAKING SAME. This clip was designed in part to overcome the difficulty encountered in the manufacture of other clips using adhesively bonded joints. The design used snap fittings in combination with a resilient polymeric composition, which yields under pressure, to snap the component parts together. Because of the large width of the slots required, as well as the resilient properties of the polymeric composition used to make the component parts, such a design as the one shown in FIG. 1 of the Cooper patent has occasionally exhibited a "scissoring" effect where the jaws do not remain in alignment used to occlude a large blood vessel or other body conduit. The "scissoring" effect produces an incomplete occlusion of the object. Hence the level of development of parallel jaw clips continues to provide opportunities for further improvements in the design and manufacture of such surgical aids.